Practically all consumer goods need protective packaging to cushion the goods during storage and transportation. It is recognised that there are numerous solutions for packaging and cushioning various goods depending on the physical properties of the goods to be protected and the degree of protection required relating to its application. Typical cushioning solutions include loose fills e.g. polystyrene pieces, paper or creped cellulose, corrugated paperboard structures (honeycomb) and foam structures (expanded polystyrene, Styrofoam, polypropylene), moulded pulp (egg trays) and inflated products (bubble wrap).
These prior art products have the disadvantages that they, in the case of loose fills, are not integrated into the packaging and may undergo granular convection, moving about the goods to be protected leaving some parts of the goods unprotected, or in the case of inflated products, may become deflated leaving the goods unprotected. Foam structures, such as expanded polystyrene, are of particular concern due to their environmental impact i.e. they are not recyclable, they do not decompose naturally once their useful lifespan is expired and they produce toxic gases on burning. The ever increasing price of crude oil also makes the production of expanded polystyrene less commercially attractive than potential alternatives.
More recent advances in the technology provide material made from foamed cellulose. For example, GB 2 303 630 discloses a product obtained by foaming cellulose with adhesives and chemical foaming agents inside a mould of the required shape. On heating, the chemical foaming agents decompose or react to form a gas that foams the mixture. The foamed cellulose is then dried.
A different approach is suggested in JP 5 263 400 A discloses a biodegradable, porous product made from a slurry of shredded paper strips. The slurry of shredded paper strips is heated, treated with a bonding chemical and dried by vacuum in a mould to give a moulded product.
Various other technical solutions for producing porous products are known.
US2002117768 discloses layered three-dimensional products, such as three-dimensional filters formed by single layered formed from a single application of foam, or a laminate formed of several layers of different fibrous foams. The fibers in the foam are short cut fibers, having an average length of 0.05 mm (millimeters) or less. The layers are relatively thin.
WO2012006714 discloses a method of manufacturing an ultralow density composite comprising natural fibers. In the known method, an alkaline pulp is foamed produce the ultralow density foam comprising a three dimensional reticular structure comprising a diffusion interphase interlocking the natural fibers.
JP2010215872 discloses a method of producing freeze-dried porous structures from microcellulose fibres.
None of the discussed products are useful as packaging materials or as sound proofing materials or thermal insulators.